Urban noise levels have been increasing over time. High levels have been noted in the industrial setting. Several investigations have shown an increased prevalence of high blood pressure among men with prolonged and repeated exposure to industrial noise when compared to a control population. The major criticisms cited aginst previous research have been: 1) the lack of documentation of intensity and duration of workers' exposure; 2) off-the-job noise exposure has generally not been controlled for; and 3) information on other factors which can affect differences between cases' and controls' blood pressure was not collected. The primary objective of the present study is to determine whether noise-exposed individuals have an elevation in blood pressure independent of other known risk factors for high blood pressure such as obesity, alcohol intake, etc. The study population will consist of a sample of 250 male hourly workers from a noise-exposed group and 250 hourly workers from a control group. To be eligible for inclusion in the sample, an employee must be between 40 and 60 years old and must have worked at that particular plant for at least ten continuous years. The clinical exam will consist of height, weight, pulse and blood pressure and audiometric evaluation. A detailed questionnaire concerning present and past health status, present smoking habits and current alcohol consumption will be administered. Data on past military history, previous job exposure, hobbies and medication will be obtained. In addition, a battery of psychological tests will be administered to the participants in order to determine the relationship between noise, behavioral changes and blood pressure.